Impact forging



April 28, 1953 R. l.. ALCORN, JR

IMPACT FORGING 4 Sheets-Sheet l Filed 001:. 16, 1950 M, w M .m m

April 2s, 1953 R. L. ALCORN, JR 2,636,350

IMPACT FORGING Filed oct. 16, 195o 4 Sheets-sheet 2 LIQ/2,.

www4/75m April 28, 1953 R. 1 ALcoRN, JR 2,636,350

IMPACT FORGING Filed Oct. 16, 1950 4 Sheets-Sheet 3 MCL@ m .GE

4 Sheets-Sheet 4 R. L. ALCORN, JR

IMPACT FORGING Nm @am Wal/665W NNN April 2s, 195s Filed Oct. 16, 1950 NF Qmm E.

Patented Apr. 28, 1953 IMPACT FORGING Robert L. Alcorn, J r., Chambersburg, Pa., assignor Chambersburg Engineering Company,

Chambersburg, Pa., a corporation of Pennsylvania v Application Gctober 16, 1950, Serial No. 190,421

Claims.

This invention relates to control of impact forging apparatus wherein a work piece is forged by means of one or more rapidly moving rams.

The principal object of the invention is to provide an apparatus which will produce an indicating and controlling signal from the virtually instantaneous position of Ia rapidly moving ram.

The invention is well adapted for use in a forging apparatus of the type wherein two horizontally aligned rams, operated by pressurized fluid, serve to forge by impact work pieces successively interposed between them.

Another object of the invention, therefore, is to provide an indicating and controlling arrangement for use in a forging apparatus of that type.

Accordingly, the invention will be described with reference to its application to such apparatus.

In such a forging apparatus, it is desirable to have provision for diierentially controllingfthe supply of pressurized uidvto the rams to establish the exact plane of impact of the rams. In my prior Patent No. 2,615,306, issued Oct. 28, 1952, there is disclosed and claimed an apparatus of this type in which differential control of the supply of pressurized fluid to the rams is provided through the medium of a common controlling valve actuated by a motor which may be part of a Selsyn system to enable remote control. By the present invention, there is provided an indicating and controlling arrangement which includes means for sensing excess travel of either ra-m, and in which the indicating and controlling functions are instituted by such means.

Reference is now made to the accompanying drawings in which the present invention is shown applied to .a forging apparatus of the character disclosed in the above-mentioned application.

In the drawings:

Fig. 1 is a view, partly in longitudinal section and partly in elevation, of the forging apparatus embodying the invention;

Fig. 2 is a schematic illustration of the controlling arrangement employed in conjunction with the impacter rams;

Fig. 3 is a diagrammatic illustration of the electrical system for controlling the operation of the apparatus;

Fig. 4 is a diagrammatic illustration of the preferred form of the indicating and controlling circuit provided according to this invention; and

Fig. 5 shows the voltage pulse which is produced whenever one of the sensing devices 1s activated. y

Referring first to Fig. l, there 'are shown two horizontally aligned rams I0 and 10a, which are movable within uid cylinders II and IIa, the rams moving toward and away from each other during a complete cycle of operation. Removably attached to the rams are dies I2 and I2a which engage a work piece (not shown) to forge the same. The dot and dash illustration shows the rams and the dies in the forward positions.

The rams are activated during the work stroke by pressurized duid supplied to the cylinders from a commonfluid line I3 though intake conduits I4 and |401.. Preferably, the rams are activated by means of compressed air, the line I3 being connected to arsritable source of compressed air. The air is supplied to the cylinders through valve devices I5 and I5a.

The ram-containing cylinders are shown mounted on Va supporting framework I'I which may also serve to support certain controlling valves as hereinafter described. The Vsupply conduit I3 extends longitudinally through the supporting framework, as does also a common exhaust conduit (not visible) through which the air is exhausted from the cylinders during the return stroke.

Referring now to Fig. 2, illustrated therein are the controlling valves associated with the ram II) and its cylinder I I, it being understood that similar valves are provided in association with the ram Ilia and its cylinder IIa. A fluid operable valve I8 controls the air input from conduit I4 to ports I9 (one visible) which extend to the interior of the cylinder at the pressure end thereof. A second duid-operable valve 20 controls the air exhaust to conduit ZI which extends to the exhaust line. In the illustration, the valve I8 is closed and the valve 20 is open, this being the condition for exhaust. When the valve 2li is closed and the valve I8 is open, air is admitted to the cylinder from conduit I4.

It should be noted that the ports I9 arespaced from the driving endV of cylinder II, and a bypass port 22 is disposed at the end of the cylinder and is arranged to by-pass the ports I9 through a spring-biased check valve 23whose spring tends to maintain it closed. The purpose of this will be explained presently.

,Referring still to Fig. 2, the inlet Valve I8 for the ram I and its associated cylinder II is controlled by pressurized duid, preferably compressed air, through a conduit 24 extending to casing 25 of a differential controlling valve 25. In like manner, the input valve for the other ram and its associated cylinder is controlled through the fluid conduit 2'! which extends from said input valve to the other side one of the supply line conductors through connections |09 and |||l.

Considering the operation of the apparatus as thus far described, the operator first closes the line switch 62 and then presses the push button start switch 66, whereupon the contactor 65 is energized and locks itself in. The contactor remains energized until such time as the operator presses the push button stop switch 61 which is connected in the holding circuit of the contactor. The energization of the contactor starts the motor 11 which runs continuously until the contactor is deenergized. Consequently, the switches 8B and 89 are cyolically operated by their motor driven cams 86 and 81. The operating sequence provided by the design of the cams is such that switch 83 first conditions the timer 63 for operation and the solenoid 42 is energized by the timer to cause operation of the rams through their power stroke, and the switch 83 closes after switch 88 opens to energize solenoid 51 which causes return of the rams.

As previously mentioned, the purpose of valve 26 (Fig. 2) is to control differentially the lsupply of iiuid to the input valves for the two rams, thereby to control the relative timing of the operation of the input valves and thus establish the exact plane of impact of the rams. In accordance with the present invention, the valve 26 is automatically controlled by position-sensing devices III and II2 (see Fig. 1) associated respectively with the two rams, the said devices serving to control the operation of the actuating motor 31 for valve 2E through the medium of the controlling circuit shown in Fig. 4.

Referring to Fig. 1, the position-sensing devices III and H2 are shown mounted on a common supporting bracket ||3 which spans the space between the ram cylinders I I and IIa, and the ends of which are secured to said cylinders. As may be seen from the cross-sectional illustration of the device I I I, each of the sensing devices may comprise a permanent magnet core l I4 and a surrounding coil I I5, both enclosed in a magnetic casing or housing I I 6 except for a small clearance around the extended end of magnet I 4. The two sensing devices are exactly located so that the lower end of each core magnet is slightly above the path of travel of the associated ram and is so positioned that the magnetic field of the core magnet will be substantially affected only if the associated ram eX- ceeds its intended extent of travel. In other words. if the plane of impact of the two rams is exactly centered, neither of the sensing devices III and ||2 will be affected sufciently to cause any corrective action. However, if the plane of impact shifts due to unbalanced operation of the rams, one of the rams will over-travel and will activate the associated sensing device to cause a corrective action as hereinafter described. The activation of either sensing device is produced by a substantial change in the distribution of the magnetic lines of force of its core magnet due to suiiicient entry of the ram into the magnetic eld to produce such change. This action causes a voltage surge in the coil of the sensing device, which surge is in the form of a pulse as represented at II1 in Fig. 5.

Referring now to Fig. 4, there is shown a circuit arrangement by which the sensing devices I I I and I I2 are caused to control the operation of the actuating motor 31 for the valve 2S. Power supply conductors IIB, which may be connected to the same source as the supply conductors of Fig. 3, extend through a manual on-oi switch H9v to a conventionalrectler unit |20 which provides D. C. operating voltages for two thyratrons I2I and |22. The rectifier unit |20 requires no detailed description and it sufices to note that the operating voltages for the thyratrons are derived from series-connected resistors |23 and |24, the latter extending to ground. The anodes of the thyratrons are connected through indicator lamps |25 and |26, and through the cam-operated switch 3|, to a tap on resistor |23. As previously described and as shown in Fig. 3, the switch 9| is cyclically operated by virtue of the fact that it is part of the motor driven switch mechanism 64. The cathodes of the thyratrons I 2| and 22 are connected to a tap on resistor |24. It will be seen that when the switch 9| is closed, the anodes of the thyratrons are at a predetermined positive D. C. voltage relative to the cathodes.

The control grid circuit of thyratron I2I extends through a resistor |21 and the coi1 of sensing device I I I in series to ground, a by-pass condenser |28 being connected as shown. Similarly, the control grid circuit of thyratron |22 includes resistor |29, the coil of sensing device I I2, and a by-pass condenser |30. Normally, the control grids of the thyratrons are suiiiciently negative relative to the cathodes to prevent operation of the thyratrons, but when a voltage surge is produced in either of the sensing devices I I I and I I2, the grid of the associated thyratron is driven in the positive direction sufficiently to iire that thyratron, assuming of course that the switch 9| is closed.

The operating motor 3'! for valve 26 is energized through branch supply conductors |3| under control of relays |32 and |33 whose windings |34 and |35 are included respectively in the anode circuits of thyratrons I2I and |22 in shunt with the indicating lamps |25 and |26. The motor 31 is a conventional reversible single phase motor having a start winding |36 and a run winding |31. These windings are connected as shown to the contacts of the two relays and to the supply connections I3I. Normally, the two relays are deenergized and their contacts are open. When relay |34 is energized, closure of its contacts causes the motor 3l to run in the forward direction, while when relay |35 is energized closure of its contacts causes the motor 31 to run in the opposite direction. It will be understood, of course, that only one of the relays is energized at a time.

The operation of the controlling and indicating circuit of Fig. 4 as a part of the over-all operation may now be understood. The manual switch I I9 is closed at the same time that the manual switch 62 of Fig. 3 is closed. A pilot lamp |38 indicates closure of the switch IIS. During the operation of the impacter rams as previously described. the cam-operated switch 9| is cyclically operated, the design or shape of its operating cam 9U being such that the switch is closed at the same time that the switch 88 is closed. It will be recalled that the switch 88 controls the forward movement of the rams, as previously described. Thus, it will be seen that the switch 9| is closed to condition the thyratrons I2i and |22 for possible operation during the forward movement of the rams. Subsequent opening of the switch, of course, renders the thyratrons inoperative, and if either of the thyratrons has been fired, stops the operation thereof.

As previously mentioned, neither of the thyratrons will operate unless its control grid receives an actuating pulse from the associated sensing valve means so as to equalize the movements of said pistons.

8. In an apparatus of the class described, a reciprocally movable member, cyclically-operated switch means, a motor for driving said switch means, means controlled by said switch means for cyclicaliy operated said member, stationary sensing means adjacent to the path of travel of said member and responsive to the presence thereof, normally-inoperative means controllable by said sensing means to govern the operation of said member, and switch means driven by said motor for rendering the last-recited means operable only during movement of said member in a direc tion to approach said sensing means.

9. In an apparatus of the class described, a reciprocally movable member, cyclically-operable switch means, a motor for driving said switch means, means controlled by said switch means for cyclically operating said member, stationary sensing means adjacent to the path of travel of said member and responsive to the presence thereof, a thyratron operable by said sensing means, means controllable by said thyratron to govern the operation of said member, and switch means driven by said motor for rendering said thyratron operable only during movement of said member in a direction to approach said sensing means.

10. In an apparatus of the class described, a duid-operated reciprocally movable piston member, cyclically-operable switch means, a motor for driving said switch means, means controlled by said switch means for cyclically operating said member, stationary sensing means adiacent to the path of travel of said member and responsive to the presence thereof, valve means for governing the operation of said member, normally-inoperative means controllable by said sensing means to actuate said valve means, and switch means driven by said motor for rendering the lastrecited means operable only during movement of said member in a direction to approach said sensing means.

1l. In an apparatus of the class described, a pair of opposed reciprocally movable members, cyclically-operable' switch means, a motor for driving said switch means, means controlled by said switch means for cyclically operating said members, a pair of sensing devices associated respectively with said members and responsive to excessive travel thereof, means for differentially controlling the movement of said members, normally-operative means controllable by said sensing devices to actuate said controlling means, and switch means driven by said motor for rendering said last-recited means operable only during movement of said members toward said sensing devices.

12. In an apparatus of the class described, a pair of opposed duid-operated piston members, cyclically-operable switch means, a motor for driving said switch means, means controlled by said switch means for cyclically operating said members, a pair of sensing devices associated respectively with said members and responsive to excessive travel thereof, common valve means for diierentially controlling the movement of said members, normally-inoperative means controllable by said sensing devices to actuate said valve means, and switch means driven by said motor for rendering saidI last-recited means operable only during movement of said members toward said sensing devices.

13. In an apparatus of the class described, a

pair of opposed fluid-operated piston members, cyclically-operable switch means, a motor for driving said switch means, means controlled by said switch means for cyclically operating said members, a pair or" sensing devices associated respectively with said members and responsive to excessive travel thereof, common valve means for differentially controlling the movement of said members, means including a pair of thyratrons controllable by said sensing devices to actuate said valve means, and switch means driven by said motor for rendering said thyratrons operable only during movement or said members toward said sensing devices.

14. In combination, fluid pressure-actuated means including a member operable through a work stroke and a return stroke, means includinof a rst solenoid-operated valve for supplying pressurized fluid to said first-mentioned means so as to operate said member through the work stroke, means including a second solenoid-operated valve for supplying pressurized fluid to said first-mentioned means so as to operate said member through the return stroke, cyclically-operable switch means, a motor for driving said switch means, means controlled by said switch means for successively energizing the operating solenoids of said valves to cyclically operate said member, a third valve arranged to control the amount of pressurized iiuid supplied to said member to operate it through the work stroke, stationary sensing means adjacent to the path of travel of said member and responsive to the presence thereof, normally-inoperative means controllable by said sensing means to actuate said third valve, and switch means driven by said motor for rendering the last-recited means operable only during movement of said member through the work stroke.

l5. In combination, a pair of opposed fluid-operated piston members, means including a rst solenoid-operated valve for supplying pressurized fluid to said members so as to drive them toward each other, means including a second solenoidoperated valve for supplying pressurized fluid to said members so as to return them, cyclicallyoperable switch means, a motor for driving said switch means, means controlled by said switch means for successively energizing the operating solenoids of said valves to cyclically operate said members, a third valve arranged to control differentially the amounts of pressurized fluid supplied to said members to operate them toward each other, Sensing means responsive to excessive travel of either of said members, normally-inoperative means controllable by said sensing means to actuate said third valve so as to equalize the movements of said members, and switch means driven :by said motor for rendering the last-recited means operable only during movement of said members toward each other.

ROBERT L. ALCORN, J a.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,799,113 Miedbrodt Mar. 31, 1931 1,953,454 Wollaeger Apr. 3', 1934 2,359,961 Anthony Oct. 10, 1944 2,367,580 Hines Jan. 16, 1945 2,378,497 Phillips June 19, 1945 2,565,639 waldie Aug. 2s, 1951 FOREIGN PATENTS Number Country Date 628,619 Great Britain Sept. 1, 1949 

